Recently, there is a growing demand for solid-state image sensors such as CCD image sensors along with the widespread use of digital cameras, cell phones with cameras and the like. Color filters are used as key components of displays or optical elements of these devices, and increasingly required to be more sensitive and smaller. Such color filters typically have a colored pattern of three primary colors, i.e., red (R), green (G), and blue (B), and have the role of decomposing the light transmitted through it into the three primary colors.
One method for preparing the color filters is the pigment dispersion method. The pigment dispersion method for preparing the color filters by photolithography or inkjet printing is stable to light and heat because it uses pigments. However, it often encounters problems such as light scattering or color unevenness or roughness because pigments per se are microparticles. To overcome these problems, micronized pigments are used at the cost of dispersion stability.
An alternative to the pigment dispersion method for preparing the color filters is to use dyes as colorants. Dyes are dissolved in compositions so that they are less likely to induce light scattering or color unevenness or roughness as compared with pigments. Recently, highly robust dyes have been developed.
However, radiation-sensitive colored compositions containing dyestuffs have been reported to be likely to cause color migration between adjacent colored patterns of different hues or between laminated layers when they are heated after they have been formed into films, and solutions to these problems by polymerizing dyes have been disclosed (for example, see patent documents 1 to 5). Further, patent documents 6 and 7 describe curable negative compositions containing dyestuffs for use in color filters.